Rock drill rotation mechanism



Jan. 22, 1963 c. F. osGooD Rocx DRILL RoTATIoN MECHANISM Original Filed Aug. 3, 1960 2 Sheets-Sheet 1 INVENTOR:

Jan. 22, 1963 c. F. osGooD 3,074,381

ROCK DRILL ROTATION MECHANISM Original Filed Aug. 3, 1960 2 Sheets-Sheet 2 n f i l 'A "y I/ v /I 79 V 4| United States Patent O 3,074,381 ROCK DRILL ROTATlQN MECHANlSM Charles F. Osgood, Franklin, Pa., assignor to lloy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Continuation of application Ser. No. 47,311, Aug. 3, 1960.

This application July 12, 1961, Ser. No. 127,078 18 Claims. (Cl. 121-7) This invention relates to a rotation mechanism for a drilling implement and more particularly to a dual rotation mechanism for a hammer rock drill whereby the drill steel may be rotated either intermittently by the hammer piston or by an independent rotation motor which may supplement or supplant the intermittent rotation.

In a copending application to I. C. Curtis et al., Serial No. 804,366, tiled April 6, 1959, owned by the assignee of the present invention, the drill steel is intermittently rotated in one direction by the usual ratchet and pawl mechanism operated by the hammer piston and an indepedent rotation motor is employed to supplement or supplant the intermittent rotation as conditions may require. The independent rotation motor is reversible and when the drill steel is rotated thereby in the reverse direction, for example during uncoupling of drill steel sections, the unidirectional intermittent rotation mechanism must be rendered inoperative thereby to prevent stalling of the rotation motor and possible breakage of associated parts due to overload. In this Curtis et al. application the intermittent rotation mechanism is rendered inactive upon reversal of the independent rotation motor by moving the pawls of the ratchet and pawl mechanism out of contact with the ratchet teeth of the stationary ratchet ring, and a fluid operated piston coordinated with the motor reverse is used to throw out the pawls at the proper time.

The present invention contemplates improvements over the above known device in that the ratchet and pawl mechanism embodies yieldable means whereby upon overload of the mechanism, or in the event the pawl-release of the earlier device fails to function, the mechanism may slip to prevent stalling of the rotation motor and possible vdamage to the associated parts. The ratchet and pawl mechanism of the present invention has a rotatatble ratchet ring which is held against rotation during intermittent rotation of the drill steel and may slip upon overload so that it may rotate while the pawls remain in contact with the ratchet teeth. The slip device of the intermittent rotation mechanism of the present invention thus provides a yieldable drive which may slip upon overload to prevent stalling of the independent rotation motor and its drive.

An object of the present invention is to provide an improved rock drill rotation mechanism whereby the drilling implement may be rotated either intermittently in one direction or continuously by independent motor means in reverse directions. Another object of this invention vis to provide an improved ratchet and pawl mechanism operated by the hammer piston, which embodies frictional slip means whereby when the independent rotation motor is reversed the ratchet ring may slip to prevent stalling of the rotation motor and possible damage to associated parts. Yet another object is to provide an improved ratchet and pawl mechanism which is yieldable upon overload. A still further object is to provide an improved rotation mechanism having both irictionally controlled unidirectional intermittent rotation means and an independent reversible motor operated rotation means, and having improved means for releasing the frictional control of said intermittent rotation whenever the independent motor rotation is reversed, thereby to prevent stalling of the independent motor and possible damage to associated parts due to over- ICC load. A still further object is to provide such a rotation which is fluid operated and having control valve means for controlling the frictional control means and the independent motor operated rotation means. Still another object is to provide such a dual rotation mechanism for the drill steel of a hammer rock drill, having a yieldable device set to slip upon overload thus to prevent damage to the associated parts. These and other objects and advantages of the invention will, however, hereinafter more fully appear in the course of the ensuing description.

This application is a continuation of my copending application Serial No. 47,311, filed August 3, 1960, now abandoned.

In the accompanying drawings there are shown for purposes of illustration a preferred form and several modications thereof which the invention may assume in practice.

In these drawings:

FIG. l is a central longitudinal vertical section through a hammer rock drill in which a preferred form of the improved rotation mechanism is employed, showing both the unidirectional intermittent rotation and the independent continuous motor rotation.

FIG. 2 is an enlarged detail section showing a modiied form of iluid piston loading means for the frictional slip device for controlling rotation of the ratchet ring.

FIG. 3 is an enlarged cross section taken on line 3-3 of FIG. l, showing the ratchet and pawl mechanism and a portion of its frictional control.

FIG. 4 is a diagrammatic View showing the fluid control system.

FIG. 5 is a cross sectional view similar to FIG. 3, 'showing a modified form of releasable slip control means for the ratchet and pawl mechanism.

FIG. 6 is a cross section similar to FIG. 5 showing another modiied frictional control for the lratchet ring.

The hammer rock drill in which the present invention is employed may be of a conventional design generally like that disclosed in the J.C. Curtis Patent No. 2,224,861, dated December 17, 1940, also owned by the assignee of the present invention.

The rock drill, as shown in FIG. l of the drawings, comprises a motor cylinder 1 having a bore 2 containing a reciprocable hammer piston 3 having a forwardly extending striking bar 4 for delivering impact blows to the shank 5 of a sectional drill steel 6 adapted to carry a usual rock drill bit, not shown. The motor cylinder has a rear head block or casing head 7 and a front chuck housing 8, and the block and housing are suitably attached to the opposite ends of the motor cylinder. The

lcylinder bore is formed in a liner sleeve 9 which is held axially forwardly against a shoulder provided by an annular ange 10 .on the cylinder, and a rear plate 11 seats against the rear end of the sleeve as shown. Arranged between the head block 7 and the rear plate 11 is a ratchet ring 12 and cooperating front and rear valve box elements 13 and 14 which cooperate to provide a chamber 15 containing cooperating relatively reciprocable dual distributing valves 16 and y17, similar to the valves disclosed in the above mentioned Curtis patent.

The motor cylinder has a front head or buffer ring 18 formed with a front flange engaging the interior cylinder ilange 10 and having its rearward portion fitting within the bore of the cylinder sleeve 9 as shown. The piston striking bar 4 extends through and is guided within t-he bore of the buier ring 18 and extends within a rotatable chuck sleeve 19 rotatably mounted within the chuck hou-sing 8 and connected as by usual separable clutch teeth 20 to a rotatable driver 211 likewise rotatably mounted within the chuck housing. The driver has interior lugs 22 engaging the usual lugs 23 on the drill steel shank whereby the drill steel may rotate with the chuck sleeve 19 as the drill steel is percussively actuated. The steel shank is .guided in a usual bushing 24 fitted within the chuck sleeve. The drill steel is reciprocably and rotatably guided within a front bushing 25 tted within the front chuck housing and retained therein by a detachable front cap 26 threaded on the chuck housing in a usual manner. Now referring to the ratchet and pawl type rotation mechanism it will be noted thatra rotatable pawl carrier 29 has an integral rifle bar 3i) extending axially forwardly through a sleeve 31 providing the internal wall of the valve chamber and through the rear plate 11, and this rifle bar has spiral grooves 32 slidingly interlocked with spiral varies 33 of a rifle nut 34 threadedly secured Within the piston head. Formed exteriorly on the piston striking bar 4 are grooves 35 slidingly interlocked with straight vanes 36 of a chuck nut 3-7 secured within the rearward portion of the rotatable chuck sleeve 19. The pawl carrier 29 carries spring pressed pawls 39 which engage the ratchet teeth 39 of the ratchet ring 12, as shown in fFG. 3.

The hammer motor is of the well known pressure fluid actuated type and embodies usual ports and passages alternately controlled by the distributing valves 16 and 17 which are also iiuid actuated, for supplying fluid under pressure to the opposite ends of the cylinder bore 2 at the opposite sides of the piston head for effecting reciprocation of the hammer piston 3 thereby to effect delivery of repeated impact blows to the shank of the drill steel in a well known manner. As the hammer piston 3 moves forwardly to effect its working stroke, i.e., to deliver an impact blow to the drill steel, the spirally grooved rifle bar 30 turns the pawl carrier 29 in a counterclockwise direction as viewed in FIG. 3, causing the pawls 38 to slip over the ratchet teeth 39 so that during the forward piston stroke no rotation is imparted by the hammer piston thereby to permit an unimpeded blow to be delivered to the drill steel. During the reverse stroke of the hammer piston, i.e., during the non-working stroke, the pawls 38 engage the ratchet teeth 39 of the ratchet ring to hold the ri-e bar 30 against rotation thereby causing the hammer piston to rotate and such rotation of the hammer piston is transmitted through the straight grooves 35 and the vanes 36 of the chuck nut 37 to the rotatable chuck sleeve 19 and thence to the driver 21 to elect partial rotation of the drill steel. Thus during operation of the drill hammer motor the drill steel is intermittently rotated in one direction, in a well known manner.

Now referring to the independent motor rotation mechanism 4for lthe drill steel it will be noted that attached t0 the forward portion of the motor cylinder is a housing 41 having a bore 42 for receiving the forward cylindrical portion 43 of the motor cylinder as shown in FIG. 1. This housing has a gear chamber 43 4closed by a rear head member 44 having a rearward sleeve portion 45 fitting within the portion of a front bore `46 in the motor cylinder. The front wal1f47 of this :gear housing has an opening 48 for receiving the rear sleeve portion 49 of the front chuck housing 8 and the latter Iabuts the -front face of the housing as shown. Formed in the housing 41 is a motor chamber 50 containing a vane type rotor 51 of a conventional reversible independent rotation motor for the drill steel. It is apparent that various other suitable types of rotation motors may be employed if desired.

A control valve device 52 has a manual operating handle 53 for controlling flow of pressure uid relative to the reversible rotation motor for controlling the direction of operation thereof. This rotation motor may be used not only in rotating the drill steel during normal drilling but also may be employed fin coupling the threaded joints of the sectional drill steel and may be reversed for the purpose of disjointing drill steel sections and during the reverse operation the unidirectional ratchet and pawl mechanism must be rendered inactive as later described.

The drive between the independent rotation motor and Aso the rotatable chuck sleeve 19 may assume various forms but herein, for illustrative purposes, the motor rotor 51 is secured to a shaft 54 suitably journaled within the gear hou-sing and a rearward casing 55 for the control valve device. Secured to the shaft 54 is a spur pinion 56 meshing with a spur gear 57 journaled on a shaft 58 which is axially movably mounted in the housing. Rotatable with the gear 57 is a spur gear 59 movable into meshing engagement with teeth of a spur gear 60 mounted on the exterior of the rotatable chuck sleeve 19. A fluid operated piston 61 contained in a cylinder 62 serves to shift the shaft 58 axially to bring the gear 59 into meshing engagement with the gear 60. This drive gearing is fully dis-closed in the Curtis et al. application above referred to.

The improved unidirectional,intermittent rotation mechanism for the drill steel comprises, as shown most clearly in FIGS. l and 3, the ratchet ring 12 which is rotatably mounted within the drill casing and has suitable frictional control means for friction brake for yieldingly holding the same against rotation during intermittent unidirectional rotation of the drill steel. The rotatable ratchet ring has longitudinal peripheral grooves or slots 64 receiving internal projections 65 on the brake discs 66. The brake discs 66 are interleaved with brake discs 67 having external projections 68 keyed into the drill casing. The rear casing head or head block 7 has a cylinder 69 which receives an annular reciprocable piston 7G having projections 71 4engaging the adjacent non-rotatable brake disc so that when the piston is moved inwardly the brake discs are pressed together frictionally and yieldingly to hold the ratchet ring against rotation. Thus as the hammer piston 3 reciprocates the ratchet and pawl mechanisrn acts in a normal manner to rotate the drill steel intermittently in one direction. The control valve device 52 comprises a rotatable valve sleeve 72 having a hollow interior 73 to which pressure fluid may be supplied through a supply connection 74 (FIG. l) connected to any suitable source of lluid under pressure. The rotary valve 72 has suitable ports and passages as disclosed in the above mentioned Curtis et al. application and a peripheral groove 75 on the valve is communicable With an exhaust passage 76 (FIG. 4).

When the annular piston 70 for the brake discs is released the pressure on the brake discs is relieved thereby to permit the ratchet ring 12 to rotate thus interrupting the intermittent unidirectional rotation.

Passages 77 and 78 (FIG. 4) lead from the control valve device 52 to the opposite sides of the rotor chamber 50 of fthe reversible vane type rotary motor and the valve 72 may be positioned alternately to connect these passages either 'to supply or exhaust to effect operation of fthe rotary motor in either direction. Leading from the passage 77 is a passageway 79 communicating with the cylinder boreV 69 at lthe rear side of the annular piston 70. lf desired a separate iiuid passage may be provided at the front side of the annular piston 70 for retracting the latter although, in this instance, the annular piston may be retracted by a coil spring as later explained. Also a separate passage v80, indicated in broken lines in FIG. 4, may connect the cylinder bore 69 directly with ports in fthe valve device independently of the supply pasage V77.

In the modification shown in FIG. 2 coil springs 81 surround pinlike projections '82 on the annular piston 70 and these springs `act on the adjacent end disc of fthe disc brake, `as shown. These springs limit .the load placed on ythe brake discs so that the latter may slip upon overload to eliminate breakage of associated parts. A forward shoulder I83 is engageable by the front surface of the piston 70 to limit its forward movement within ,the cylinder bore 69. Ihe coil springs also may retract the piston 70 FIG. 5 shows a modified form of ratchet ring brake comprising a piston i85 contained within a cylinder 86 and having a plunger 87 providing a deten-t engaging circumferentially spaced peripheral recessesV 88 on the exterior periphery ofthe rotatable ratchet ring 12. When pressure uid is supplied through the passage 79 to the cylinder bore .the piston 85 is moved inwardly to bring the detent plunger S7 into engagement with one of the grooves 88 on the ratchet ring to lock the latter against rotation. Evidently the number of the grooves on the ratchet ring may be varied, as desired. When the passage 79 is vented a coil spring 89 serves to retract the piston 3S to release the ratchet ring for free rotation.

The modication shown in FIG. 6 comprises a brake band `91, instead of the brake discs, for controlling rotation of the ratchet ring. This brake band engages the circular outer braking surface 92 of the ratchet ring and has ends which are drawn together to apply the brake. One end of the brake band abuts a spring pressed plunger 93 which is adapted to yield upon overload of the brake. A piston 94 contained in a cylinder bore 95 engages the other end of the .brake band and the tluid passage 79 communicat with the cylinder bore at the outer side of the piston.

When the piston 94 is moved inwardly the brake is applied and when the passage 79 is vented the piston 94 is retracted by a coil spring 96.

From the foregoing it is evident that when .the independent rotation motor is reversed, for example during the uncoupling of drill steel joints, pressure diuid is vented concurrently from the ratchet ring brake to release the latter thereby to prevent possible stalling of :the rotation motor and breakage of the associated parts. Whenever the independent rotation motor is operated in a direction to rotate the drill steel to supplement or supplant the ratchet and pawl mechanism the brake is automatically applied to hold the ratchet ring against rotation. lf desired the ratchet ring brake may be released independently of the operation ofthe independent rotation motor.

As a result of this invention an improved hammer rock drill is provided which may operate in a normal manner with ratchet and pawl intermittent rotation of the drill steel and by the provision of the independent rotation motor and the improved control means, the independent motor may be operated to supplement the normal ratchet and pawl rotation and at times the independent motor may supplant the ratchet and pawl rotation. When it is desired to disjoint the drill steel sections, or for any other reason, the independent motor may be reversed and the ratchet and pawl mechanism is automatically rendered inactive. [Also by the provision of `the improved control means the hammer motor may be shut down during operation of the independent rotation motor. The improved frictional control device for the ratchet and pawl mechanism not only enables the latter to be rendered inactive but lalso enables automatic slipping of the intermittent rotation upon overload. These and other advantages of the invention will be clearly apparent to those skilled in the art.

While there are in this application specifically described one preferred form and several modifications which the invention may assume in practice, it will be understood that this form and these modifications thereof `are shown for purposes of illustration and that the invention may be further modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim is:

l. In a rock drill, the combination comprising a hammer motor having a cylinder containing a reciprocable hammer piston for percussively actuating a drilling implement, unidirectional intermittent rotation means for intermittently rotating the drilling implement as it is percussively actuated, frictional slip control means for said unidirectional intermittent rotation means for rendering the same ineffective, independent reversible rotation means for said drilling implement for supplementing or supplanting said unidirectional rotating means, and control means for said independent rotation means and said slip control means for effecting reversal of said independent rotation 6 means yand concurrent slippage or release of said slip control means for rendering said unidirectional rotation means ineiective.

2. A rock drill as set forth in claim 1 wherein said intermittent unidirectional rotation means comprises a rotatable ratchet ring having teeth and pawls engaging said teeth, and said slip control means comprises friotional means for holding said ratchet ring stationary during operation of said unidirectional rotation means.

3. A .rock drill as set forth in claim l wherein means -is provided for setting said frictional control means to slip upon overload to prevent damage to said unidirectional intermittent rotation means.

4. In a rock drill, the combination comprising a cylinder containing a hammer piston for percussively actuating a drilling implement, a ratchet and pawl mechanism actuated by said hammer piston for intermittently rotating the drilling implement in one direction, an independent reversible fluid actuated motor means for continuously rotating the drilling implement in either of opposite directions for supplementing or supplanting said ratchet and pawl mechanism, a fluid operated brake for holding the rotatable ratchet of said ratchet and pawl mechanism stationary to elect intermittent rotation of the drilling implement in one direcion, and control valve means for reversing said independent motor means and for concurrently ettecting release of said brake to render said ratchet yand pawl mechanism ineiiect'ive during reverse rotation.

5. In a rock drill, the combination comprising a cylin der containing a hammer piston for percussively lactuating a drilling implement, iiuid controlled frictional means for intermittently rotating -the drilling implement in one direction, an independent reversible rotation means for continuously rotating the drilling implement in either of opposite directions, and control means for regulating the control of fluid tlow to said frictional means and said independent rotation means for rendering said intermittent rotation means ineffective whenever said independent rotation means is reversed.

6. A rock drill as set forth in claim 5 wherein said intermittent rotation means includes la rotation electing element held stationary by said frictional means during intermittent rotation in said one direction and adapted freely to move when said intermittent rotation means is ineffective.

7. A rock drill as set forth in claim 6 wherein said rotation effecting element is rotatable and said frictional means comprising a tiuid operated brake for frictionally holding said rotatable element against rotation.

8. In a rock drill, a hammer motor comprising a cylinder containing a hammer piston for percussively lactuating a drilling implement, frictionally controlled unidirectional rotation means for intermittently rotating the drilling implement in one direction, reversible rotation means for continuously rotating the drilling implement in either of opposite directions, and control means for reversing said continuous rotation means and for concurrently rendering said frictional intermittent rotation means inelective by slippage of the frictional control.

9. A rock drill 'as set forth in claim 8 wherein said unidirectional intermittent rotation means has a frictional- 1y controlled rotation eiecting member provided with a fluid actuator for applying a braking pressure thereto, and said control means controls fluid flow to said iiuid actuator.

10. A rock drill as set forth in claim 8 wherein said unidirectional intermittent rotation means is irictionally controlled and is fluid operated, and said control means controls iiuid operation of said frictional control, and said frictionally controlled rotation means is adapted to slip upon overload.

ll. In a rock drill, the combination comprising a hammer motor having a reciprocating hammer piston for percussively actuating a drilling implement, unidirectional intermittent rotation mechanism operated by said hammer piston for intermittently rotating the drilling implement in one. direction, a reversible independent rotation motor mechanism for supplementing or supplanting said unidirectional intermittent rotation mechanism, and control means for eiecting reversal of said independent motor mechanism and for concurrently rendering said unidirectional intermittent rotation mechanism inactive, one of said rotation mechanisms including a slip device adapted to yield upon overload to prevent damage to the parts.

12. A rock drill as set forth in claimk l1 wherein said slip device is embodied in said unidirectional intermittent rotation mechanism, said slip device being controlled by said control means.

13. In a rock drill, the combination comprising a hammer motor having a reciprocating hammer piston for persaid rotation mechanisms including a slip device controlled byy said control means and adapted to yield upon overload to prevent damage to the parts.

14. In a drilling tool having a drilling implement, a reciprocatory motor, means operated by said reciprocatory motor for electing rotation of the drilling implement during drilling including a releasable frictional slip device for interrupting intermittent rotation, a reversible rotary motor for supplementing said reciprocatory motor in the 1 rotation of the drilling implement, and means for automatically releasing said slip device whenever said rotary motor is reversed to effect rotation of the drilling implement in the opposite direction.

15. In a rock drill, a motor for deliverying impact blows to a drilling implement, rotation means cooperating with said impact motor for intermittently rotating the drilling implement in one direction, and independent rotation means for continuously rotating the drilling implement in the opposite direction, one of said rotation means embodying a releasable slip device for interrupting rotation of the drilling implement.

16. In a rock drill, a motor for deliverying impact blows toa drilling implement, rotations means cooperating with said impact motor for intermittentlyrotating the drilling implement in one direction, independent rotation means for continuously rotating the drilling implement in the opposite direction, one of said rotation means embodying a releasable slip device for interrupting rotation of the drilling implement, and means for automatically effecting operation of said slip device to interrupt rotation of the drilling implement upon operation of said independent rotation means in said opposite direction.

17. In a rock drill, a motor for delivering impact blows to a drilling implement, rotation means cooperating with said impact motor for intermittently rotating the drilling implement in one direction, and independent rotation means for continuously rotating the drilling implement in the opposite direction, said intermittent rotation means embodying a releasable slip device for interrupting intermittent rotation of the drilling implement in said one direction.

18. A drilling mechanism comprising, in combination, a rotatable member for transmitting rotation to a drilling implement, a reciprocable element, rotation means connected to said reciprocable element for intermittently rotating said rotation transmitting member in one direction, independent rotation means connected to said rotation transmitting member for continuously rotating the drilling implement in the opposite direction, said intermittent rotation means including controllable resistance means adapted to slip upon overload and releasable to interrupt rotation of said rotation transmitting member, and control means operable at will for effecting intermittent rotation in said one direction, said control means including means for eiecting operation of said independent continuous rotation means and operable to eiTect release of said slip.- resistance means whenever said independent rotation is effected in said opposite direction.

References Cited in the le of this patent UNITED STATES PATENTS 1,176,443 Haeseler Mar. 2l, 1916 1,540,909 Smith June 9, 1925 1,709,440v Osgood Apr. 16, 1929 1,740,684 Gartin Dec. 24, 1929 2,051,053 Morris Aug. 18, 1936 2,224,861 Curtis Dec. 17, 1940 

1. IN A ROCK DRILL, THE COMBINATION COMPRISING A HAMMER MOTOR HAVING A CYLINDER CONTAINING A RECIPROCABLE HAMMER PISTON FOR PERCUSSIVELY ACTUATING A DRILLING IMPLEMENT, UNIDIRECTIONAL INTERMITTENT ROTATION MEANS FOR INTERMITTENTLY ROTATING THE DRILLING IMPLEMENT AS IT IS PERCUSSIVELY ACTUATED, FRICTIONAL SLIP CONTROL MEANS FOR SAID UNIDIRECTIONAL INTERMITTENT ROTATION MEANS FOR RENDERING THE SAME INEFFECTIVE, INDEPENDENT REVERSIBLE ROTATION MEANS 